Accession Number : ADA186933

Title :   Approximate Solutions of Heat Conduction in a Medium with Variable Properties,

Corporate Author : COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH

Personal Author(s) : Yen, Yin-Chao

PDF Url : ADA186933

Report Date : Sep 1987

Pagination or Media Count : 31

Abstract : The approximate heat balance integral method (HBIM) is extended to the case of a medium with variable properties such as snow. The case of linear variation of thermal conductivity was investigated. An alternative heat balance integral method (AHBIM) was developed. Both constant surface temperature and surface heat flux were considered. A comparison was made of the temperature distribution from the HBIM, AHBIM and an analytical method for the case of constant surface temperature. In general, results agree quite well with the analytical method for small values of dimensionless time tau, but the difference becomes more pronounced as tau increases. It was found that the AHBIM with a quadratic temperature profile gave a somewhat better result, especially when the value of the dimensionless distance eta is small. For a specific property function of E(eta) = e eta, closed form solutions were obtained. The results, when compared with those from HBIM, AHBIM and the analytical method were found to agree exceptionally well with the analytical method, especially for large values of tau. Keywords: Conduction, Heat transfer, Mathematical analysis, Snow.

Descriptors :   *HEAT BALANCE, *HEAT TRANSFER, *THERMAL CONDUCTIVITY, DISTRIBUTION, HEAT FLUX, LINEARITY, MATHEMATICAL ANALYSIS, PROFILES, QUADRATIC EQUATIONS, SNOW, SOLUTIONS(GENERAL), SURFACE TEMPERATURE, TEMPERATURE, VARIABLES, VARIATIONS

Subject Categories : Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE